ASCO: Enzalutamide effective for metastatic prostate cancer

(HealthDay News) -- Two beneficial treatment approaches are available for metastatic and locally advanced prostate cancer, according to two studies presented in advance of the American Society of Clinical Oncology's annual Genitourinary Cancers Symposium, to be held Jan. 30 to Feb. 1 in San Francisco.

Tomasz M. Beer, M.D., from the Oregon Health & Science University-Knight Cancer Institute in Portland, and colleagues conducted a multinational phase 3 study involving 1,715 chemotherapy-naive men with metastatic castration-resistant prostate cancer who were randomized to receive enzalutamide or placebo in a 1:1 ratio. At the interim analysis at 539 deaths, the researchers found that enzalutamide treatment correlated with a significant reduction in the risk of death (hazard ratio, 0.70) and in the risk of radiographic progression or death (hazard ratio, 0.19).

Sophie Dorothea Fosså, M.D., from Oslo University Hospital in Norway, and colleagues randomized 875 patients with locally advanced prostate cancer to receive hormonal treatment only or androgen blockade followed by radiotherapy and continuous anti-androgen therapy in a 1:1 ratio. The researchers observed significantly more prostate cancer deaths in the hormone treatment group (118/439) versus the combination group (45/436; P < 0.0001), with all-cause death occurring in 210 and 161 patients, respectively (P = 0.0006). After combination treatment, the 10-year cumulative prostate cancer-specific mortality and overall mortality were significantly reduced (hazard ratios, 0.35 and 0.70).

"This combination more than doubles the 10-year survival rate and confirms that this approach should be a standard option for men with this type of prostate cancer who are expected to live at least another 10 years," Fosså said in a statement.

Several authors from the Beer study disclosed financial ties to pharmaceutical and biotechnology companies, including Astellas Pharma and Medivation, which manufacture enzalutamide.